Integration between Modeling and Experiments for Crystalline Metals: From Atomistic to Macroscopic Scales IV: Session IV
Sponsored by: TMS Advanced Characterization, Testing, and Simulation Committee, TMS Materials Characterization Committee, TMS: Nanomaterials Committee
Program Organizers: Arul Kumar Mariyappan, Los Alamos National Laboratory; Irene Beyerlein, University of California, Santa Barbara; Levente Balogh, Queen's University; Caizhi Zhou, University of South Carolina; Lei Cao, University of Nevada; Josh Kacher, Georgia Institute of Technology
Tuesday 8:00 AM
October 11, 2022
Room: 404
Location: David L. Lawrence Convention Center
Session Chair: Adrien Couet, University of Wisconsin-Madison; Brandon Wood, Lawrence Livermore National Laboratory
8:00 AM Invited
Multiscale Modeling of the Microstructural Dependence of Degradation Initiation in Al and Ti: Brandon Wood1; Tuan Anh Pham1; Tae Wook Heo1; Christine Orme1; Jennifer Rodriguez1; James Chapman1; Tim Hsu1; Yakun Zhu1; Ryan Mullen1; Nir Goldman1; Seongkoo Cho1; Nathan Keilbart1; Kyoung Kweon1; 1LLNL
Degradation of structural metals carries significant cost burdens. The earliest stages of degradation are often difficult to characterize, making computational methods imperative for assessing structure-property relations if the large range of spatiotemporal scales can be spanned. Our team has been developing and applying multiscale approaches, combined with detailed characterization, to understand early-stage metal degradation via two distinct modes: hydriding and aqueous corrosion. First, I will show how atomic-scale grain boundary models can be combined with graph-theoretic approaches and mesoscale models to predict the effects of microstructure and local atomic structure on the hydrogen permeability of Ti and its native oxide layer. Second, I will show how the microstructural dependence of aqueous corrosion kinetics of polycrystalline Al can be deciphered by combining grain orientation-aware electrochemical kinetics simulations, local-probe characterization, and graph neural network approaches. Performed under the auspices of the U.S. DOE by LLNL under Contract DE-AC52-07NA27344.
8:30 AM
Calibration, Validation, and Application of a Digital Twin for a Standard End-chilled Plate Casting: Mohamad Daeipour1; Cayman Cushing1; Matthew Carragher1; Serge Nakhmanson1; Harold Brody1; 1UConn
Our current focus is developing a digital twin for an end-chilled plate casting that can be used for combined computational and physical simulation of casting, solidification, and heat treatment processes in advanced aluminum alloys. The thermal physical properties of the mold materials are calibrated by physically casting and simulating the casting and solidification of pure aluminum in a standard (benchmark) end-chilled plate mold. The reliability of the calibrated digital twin for simulating thermal and solidification parameters in the standard mold is validated with hypo-eutectic aluminum-copper alloys, for which thermal-physical parameters and solidification kinetics are well documented. Then, the validated standard mold and its digital twin are applied to the more complex and not as well documented multicomponent aluminum alloys A356/A357. Measurements on the physical model combined with inverse computations with the digital twin afford expanded thermal physical property and solidification kinetics databases and improved and expanded quantitative quality criteria (predictors).
8:50 AM
Modelling of Quenching of Low Alloy Steels: Ashley Scarlett1; Eric Palmiere1; Daniel Cogswell1; 1The University of Sheffield
This paper models the behaviour and microstructural evolution of SA508 Grades 3 and 4N steels using thermodynamic and kinetic modelling via JMatPro, and finite element modelling via DEFORM, during water quenches from austenitisation temperatures. Results from JMatPro are experimentally corroborated using data from the literature. Grades 3 and 4N are used to give a comparison of microstructures, and therefore some indication of mechanical performance, between two grades that are commonly used in structurally relevant components in the nuclear industry. DEFORM results are compared to thermocoupled Jominy end quench tests in order to guide further modelling. To conclude, large steel sections show microstructures that are typically less hard and tough toward the centre of the component, with much slower cooling rates and that SA508 Grade 4N is more hardenable than Grade 3. This research will be the basis of further heat treatment studies.
9:10 AM
Experimental Data for Casting Process Simulation Validation: Jonah Duch1; Mathew Hayne1; Meghan Gibbs1; 1Los Alamos National Laboratory
Process modeling, such as casting simulations, are important tools that are used to reduce development time and predict part quality. The greater the accuracy of these simulations, the more useful they are as a predictive tool. Detailed knowledge of the specific boundary conditions and material properties during the entire casting process is required to ensure the simulations can predict a defective part before it is cast. In this work, casting experiments using a vacuum induction furnace provide heat transfer data and emissivity values for multipart molds, various mold geometries, and mold coating thicknesses. This data will be used to refine the casting simulations as they are sensitive to small changes in these values.These changes in casting conditions will lead to differences in the thermal history of a cast part. Using the heat transfer, emissivity, and cooling rate data, a greater understanding of the processing – microstructure relationship is obtained.
9:30 AM
Predicting Yield Strength in β-NiAl + Cu + VC Triple Nano-precipitate Strengthened Austenitic Steel: Colin Stewart1; Edwin Antillon1; Richard Fonda1; Keith Knipling1; Patrick Callaham1; Paul Lambert2; 1US Naval Research Laboratory; 2US Naval Surface Warfare Center, Carderock Division
A novel series of Mn-stabilized Austenitic steels strengthened by nano-precipitates has been developed using integrated computational materials engineering (ICME). These steels can achieve impressive hardness values over 560 HV (estimated σy ~200 ksi). An Austenitic Fe–17.7Mn–10.0Ni–5.0Al–4.7Cr–4.0Cu–1.0V–0.48C (wt.%) alloy produces three nano-scale phases upon ageing: (i) insoluble Cu; (ii) intermetallic β-NiAl; and (iii) VC. In these alloys, the microstructures as observed by atom probe tomography (APT) will vary not only on alloy composition, ageing time and temperature, but will also depend on precipitation synergies between phases (i-iii). Factors that may influence the yield strengths of these materials include the volume fractions, number densities, size distributions, and morphologies of the precipitate phases. This presentation will discuss modeling the yield strength of these alloys using microindentation, microstructural data from APT, molecular dynamics, and theoretical models. Comparisons will also be made between experimental data vs ICME tools such as TC-PRISMA.
9:50 AM Break
10:10 AM Invited
Designing Stable θ'/L12 Co-precipitates in Cast and Additively Manufactured Al-Cu-Mn-Zr Alloys: Jonathan Poplawsky1; Richard Michi1; Lawrence Allard1; Sumit Bahl1; Dongwon Shin1; Alex Plotkowski1; Amit Shyam1; 1Oak Ridge National Laboratory
𝜃´ precipitates (Al2Cu) strengthen Al-Cu alloys, but coarsen and transform after relatively short >250C exposures. Luckily, Mn and Zr microsolute additions stabilize 𝜃´ for lengthy 350C exposures. Advanced microscopy and computational techniques reveal that interfacial Mn segregation stabilizes 𝜃´ for a long enough time to allow slower diffusing Zr atoms to form an L12 structure at coherent-𝜃´ interfaces. Atom probe tomography reveals continuous interfacial Zr segregation for up to 350C, 5,000h exposures and a Zr matrix content dependent segregation rate. Zr segregates to 𝜃´ interfaces an order of magnitude faster within additively manufactured Al-Cu-Mn-Zr due to a supersaturated matrix forming L12/𝜃´ co-precipitates after short aging times. 𝜃´ serves as a perfect template for forming stable planar L12-Al3Zr precipitates that remain after Cu dissolves from 𝜃´ for >350C exposures. Microscopy was conducted at ORNL’s CNMS, which is a U.S. DOE Office of Science user facility.
10:40 AM
Monte Carlo Simulations for Synthetic Microstructure Generation of M23C6 Precipitation in 347H Stainless Steels: William Frazier1; Shoieb Chowdhury1; Arun Sathanur1; Mohammed Taufique1; Ram Devanathan1; Keerti Kappagantula1; 1Pacific Northwest National Laboratory
A Monte Carlo simulation method capable of modeling the phase transformation behaviors of 347H stainless steels was developed for the purpose of producing synthetic microstructures that approximate its microstructural evolution under aging periods of up to 10,000 hours at temperatures between 550 °C and 750 °C. To accomplish this, experimental data from the literature was used to properly parameterize simulations and replicate the nucleation and growth kinetics of M23C6 particles within the alloy. These simulations were found to have considerable fidelity to previous efforts for modeling the precipitation of M23C6 in other 300 series stainless steel alloys when adjusted for aging temperature, duration, and carbon composition. Synthetic 347H microstructures were then generated that accounted the effects of aging temperature, duration, creep conditions, and the presence of boron within the microstructure. Current efforts to expand our modeling to incorporate additional precipitation behaviors are also discussed.
11:00 AM
Nanoscale Plasticity in Irradiated Inhomogeneous Alloys: Yash Pachaury1; Anter El-Azab1; 1Purdue University
We present a data-driven multiscale computational framework based on discrete dislocation dynamics (DDD) for investigating the effects of irradiation on the mechanical behavior of small scale FeCrAl specimens. Irradiation induced defects such as a/2<111> and a<100> prismatic loops, and composition fluctuations/α’ precipitates play a critical role in governing the mechanical behavior of alloys hence influencing their in-service longevity in nuclear environments. This along with the size effects in small scale specimens make the irradiation physics more intriguing. In this presentation, we report on the combined as well as separated effects of different irradiation induced defects along with the effects of loading orientations on the mechanical behavior of the irradiated nanoscale FeCrAl alloys.
11:20 AM Invited
A Blessing in Disguise: Irradiation Damage Helps Slow Down Alloy Corrosion Rate via Oxide Space Charge Compensation Effects: Adrien Couet1; Zefeng Yu1; Elizabeth Kautz2; Hongliang Zhang1; Anton Schneider1; Taeho Kim1; Yongfeng Zhang1; Sten Lambeets2; Arun Devaraj2; 1University of Wisconsin-Madison; 2Pacific Northwest National Labratory
Radiation effects in materials often compound and accelerate other detrimental phenomena such as embrittlement, oxidation and creep. However, irradiation can also decrease the oxidation rate, for instance with ZrNb alloys nuclear fuel cladding. In this study, we rationalize this observation by introducing a mechanism based on oxide space charge modification, resulting from irradiation enhanced Nb clustering. This mechanism is evidenced by a multiscale approach from macroscale, to determine post-irradiation oxidation kinetics, to atomic scale using in-situ atom probe tomography sample oxidation, to observe elemental solute redistribution across the oxide/metal interface. The mechanism is further supported by high resolution transmission electron microscopy characterization and density functional theory calculations. A point defect model is proposed to account for oxide space charge effects and their changes under irradiation. This integrated, multiscale experimental and modeling approach challenges the current paradigm on irradiation effects and how they can potentially improve materials performance in extreme environments.